CFC DNA Analysis & Interpretation 4

Question 1

Which quality assurance standard governs accredited forensic DNA laboratories in the United States?

Accepted Answer

FBI Quality Assurance Standards (QAS) for Forensic DNA Testing Laboratories

Answer

The FBI's Quality Assurance Standards for Forensic DNA Testing Laboratories set mandatory requirements for all laboratories submitting profiles to CODIS.

Question 2

What is the purpose of a 'negative control' in a forensic DNA amplification run?

Accepted Answer

To detect contamination by showing no DNA amplification in the absence of a sample

Answer

A negative control contains all reagents except a DNA template; any amplification signals contamination of the reagents or process.

Question 3

In probabilistic genotyping, what does a likelihood ratio (LR) greater than 1 indicate?

Accepted Answer

The evidence is more likely if the suspect contributed than if an unknown person did

Answer

An LR > 1 means the observed DNA evidence is more probable under the prosecution hypothesis (suspect contributed) than the defense hypothesis (unknown contributor).

Question 4

A forensic DNA laboratory receives a reference swab and a crime scene sample. Before comparison, the analyst confirms the samples were collected and stored separately. Why is this critical?

Accepted Answer

To prevent contamination and ensure the reference did not inadvertently transfer DNA to the evidence sample

Answer

Separate handling and storage of reference and evidence samples prevents cross-contamination that could create a false association.

Question 5

Which forensic scenario is best addressed by familial DNA searching in a CODIS database?

Accepted Answer

Identifying an unknown suspect through a close relative whose profile is in CODIS

Answer

Familial searching looks for partial matches in CODIS that may indicate a close biological relative of the unknown contributor, potentially leading to an unidentified suspect.

(CFC) Certified Forensic Consultant Practice Test

(CFC) Certified Forensic Consultant Practice Test

CFC DNA Analysis & Interpretation 4